{"mensaje":"Este endpoint requiere POST con JSON, ej: {\"headers\":\"From: Bank <security@bank-example.com>\\nReply-To: support@other-domain.ru\\nAuthentication-Results: mx.google.com; spf=pass; dkim=fail; dmarc=fail\\nSubject: Verify your account\"}. Precio: $0.003 USDC (Solana o Base)."}